More than 64,000 US pediatric patients/year are diagnosed with ARDS (Acute Respiratory Distress Syndrome) - a life-threatening lung dysfunction in many cases related to lung edema, with a 30-40% fatality rate. The onset, progression, and treatment of ARDS can be monitored by measuring patient Extra-Vascular Lung Water (EVLW). However, current radiological, pressure, and oxygenation methods for measuring EVLW are unreliable in practice and cannot quantify EVLW. And due to patient small vessel sizes, existing dilution-based EVLW measurement technologies used for adults cannot be applied routinely in pediatric ICUs. A less-invasive method for detecting and quantifying EVLW could allow physicians to better manage pediatric ARDS;could reduce the duration of mechanical ventilation;and could reduce patient morbidity and mortality. Transonic Systems will address this need by developing a new dilution-based EVLW technology that uses the patient's existing arterial and venous cannula. EVLW measurements will only require installation of a disposable extracorporeal loop between the cannula and injections of small-volume cold saline. The Phase-I research will develop a double-indicator ultrasound-thermodilution approach to EVLW measurement. This will involve designing a prototype extracorporeal AV loop that incorporates a fast-reaction thermal sensor and prototype software for automatically calculating EVLW. The Phase-I system will be tested in a porcine lung injury model, with results validated by gravimetric lung water measurement. Success in meeting Phase-I goals will guide Phase-II research to develop and clinically evaluate a prototype lung water measurement device for use in pediatric ICUs. PUBLIC HEALTH RELEVANCE: This technology will improve pediatric patient health by allowing in-time diagnosis of lung edema, which would allow physicians to adjust treatments and ensure adequate oxygen delivery. This could reduce patient morbidity and mortality and ultimately reduce short and long-term health care costs. This device would be commercially successful because pediatric ICUs currently do not have a minimally invasive tool for detecting and measuring extravascular lung water in patients suffering from ARDS and/or sepsis.